U.S. President Donald Trump on Tuesday, March 13 said he had replaced U.S. Secretary of State Rex Tillerson with Central Intelligence Agency Director Mike Pompeo, and had tapped Gina Haspel to lead the CIA, Reuters reports.

The resignation represents the biggest shakeup of the Trump Cabinet so far and had been expected since last October when reports surfaced about a falling out between Trump and Tillerson, 65, who left his position as chief executive of Exxon Mobil to join the administration.

U.S. stock index futures pared their gains and the dollar also trimmed gains versus the yen while extending losses versus the euro amid the news.

Trump publicly undercut Tillerson’s diplomatic initiatives numerous times, including on Monday when the former secretary of state’s comments about Russia appeared to be at odds with those of the White House.

Tillerson also appeared out of the loop last week when Trump announced he would meet with North Korea’s leader and become the first sitting U.S. president to do so.

“Mike Pompeo, Director of the CIA, will become our new Secretary of State. He will do a fantastic job! Thank you to Rex Tillerson for his service! Gina Haspel will become the new Director of the CIA, and the first woman so chosen. Congratulations to all!” Trump said on Twitter.